Yes, this sounds very desirable. Ideally the bot would create a test project on OBS, build the forked Git repo head (at least) and make the results (OK/KO, built RPMs and rpmlint / build log) available. Other than the green/yellow/red dot, the bot could add links the build artifacts e.g. in a comment on a commit.
you can have that by using the already existing git scm workflow, no need to reinvent the wheels in the scm-staging bot.
Adding a comment on a commit sounds doable, albeit it would have to get continuously updated.
There is a status api where you can attach a testing status (build status) to each git commit. please don't do it as comments, this is imho quite messy and distracts from human review comments (it is sort of bearable in BCI-dockerfile-generator because it rarely gets review comments). Greetings, Dirk